Optical networks utilize Reconfigurable Optical Add-Drop Multiplexers (ROADMs) to realize selective and reconfigurable add/drop of wavelengths or spectrum locally and between various degrees. ROADMs generally utilize Wavelength Selective Switches (WSSs) in different configurations. Flexibility in add/drop requirements has led to so-called colorless, directionless, and optionally contentionless add/drop multiplexer structures, such as in ROADM devices, nodes, architectures, and structures. A colorless add/drop device supports any wavelength or spectral occupancy/band being added to any port of an add/drop device, i.e., ports are not wavelength specific. A directionless add/drop device supports any port being directed to any degree. Finally, a contentionless add/drop device supports multiple instances of the same channel (wavelength) in the same device (albeit to different degrees). A colorless, directionless add/drop device can be referred to as a CD device, and a colorless, directionless, and contentionless add/drop device can be referred to as a CDC device.
CDC ROADM deployments are common and offer the most flexibility, albeit at higher costs and equipment requirements. Of note, conventional CDC configurations are less cost effective for smaller degree nodes. For this reason, network operators typically opt for CD or Colorless Direct Attach (CDA) configurations for smaller degree nodes (e.g., four or fewer degrees). It would be advantageous to provide a configuration which supports CDC in smaller degree and add/drop nodes with lower costs and equipment requirements.